Cost effectiveness of influenza vaccination for healthy persons between ages 65 and 74 years.

Healthy persons between 65 and 74 years of age represent a large proportion of the population in this age group. Internationally, there is a substantial variation in whether these people are included among the recommendations for routine influenza vaccination. We therefore conducted this study, updating an earlier analysis, to assess the health and economic benefits of routine influenza vaccination of healthy persons between 65 and 74 years of age. The health benefits associated with vaccination were estimated using the administrative data bases of a large HMO in the Minneapolis, St. Paul, Minnesota area. Multivariate models were used to estimate reductions in hospitalization and death associated with vaccination. The economic analysis took the societal perspective and presented the results as net cost or saving per 10,000 persons vaccinated and per death prevented. Direct and indirect monetary costs were included in the models and were estimated from the published literature. Monte Carlo simulation was used to conduct probabilistic sensitivity analysis in order to derive probability intervals for each estimate of net costs or savings. Over the six consecutive study seasons, 1990-1991 to 1995-1996, vaccination of healthy elderly person was associated with a 36% reduction in hospitalization for pneumonia or influenza (95% CI, 2-39%), an 18% reduction in hospitalization for all respiratory conditions (95% CI, -6 to 37%) and a 40% reduction in death (95% CI, 14-38%). Vaccination was also associated with cost savings in all scenarios evaluated. The findings of this study again affirm the value of an age-based strategy for routine influenza vaccination of all elderly persons including healthy elderly persons between 65 and 74 years.